Disclosed embodiments relate to a method for predicting the temperature of a wheel bearing of a wheel of a vehicle, to a device for carrying out the method and to the use of the predicted temperature.
Nowadays, diagnostic and monitoring systems are being increasingly used in rail vehicle traffic, the diagnostic and monitoring systems detecting changes in state of components and assemblies of the rail vehicle in order to detect defects in these components and assemblies. In particular in the case of a wheel set of a rail vehicle the detection of damage is of particular interest in terms of hot running.
Modern high speed trains travel across borders and must therefore meet corresponding criteria in order to ensure inter-operability, for example the 96/48/EG guideline. The guideline requires, inter alia, onboard monitoring of the wheel set bearings of the wheel sets of the rail vehicle. In order to reveal critical operating states such as, for example, hot running of a wheel set bearing, in particular monitoring of the temperature of the wheel set bearings is necessary.
EP 1 365 163 A1 discloses a device for monitoring the temperature of a wheel set bearing of a wheel set of a rail vehicle in which a sensor element is arranged directly on a sealing element of the wheel set bearing, i.e. as close as possible to the load zone of the wheel set bearing. However, mounting of a temperature sensor directly on the load zone of a wheel set bearing on which the maximum temperatures have been empirically found to occur, i.e. at the top when viewed in the circumferential direction of the outer bearing ring, requires a certain amount of expenditure on mechanically connecting the temperature sensor and on its cabling and is often structurally difficult to implement for reasons of space, in particular if multiple load zones have to be taken into account within a bearing unit, for example in the case of double bearings. As a rule it is therefore difficult to measure the temperature in the load zone of the wheel bearing. However, if the temperature profile is measured at measuring points which differ from or are remote from the load zone, for example at a bearing cover of the wheel bearing, these signals have time delays owing to the thermal junction between the load zone and the measuring point, which time delays also delay a diagnostics or interpretation of the measured temperature.
If, for example, a rail vehicle has a speed of 300 km/h and the critical temperature of a wheel bearing is 110° C. and this temperature is reached with a high temperature gradient, in the case of temperature monitoring of the prior art automatic braking is initiated when the critical temperature is reached. However, the temperature of the respective wheel bearing will still rise significantly for a specific time, i.e. the bearing temperature can exceed the critical temperature, with the threat of damage to the bearings.